1. Field of the Invention
The present invention generally relates to a light emitting diode (LED), and more particularly to an LED which can provide a uniform illumination.
2. Description of Related Art
Light emitting diodes (LEDs) are a commonly used light source in applications including lighting, signaling, signage and displays. The LED has several advantages over incandescent and fluorescent lamps, including high efficiency, high brightness, long life, and stable light output. The LED creates much higher illumination and space brightness with less electricity consumption.
A conventional LED generally includes a base, a chip mounted on the base, and an encapsulation sealing the chip. The encapsulation is made of a transparent or translucent epoxy resin and usually has an output surface. The LED emits light rays towards the output surface. A portion of the light rays, especially those incident on lateral parts of the output surface, will be reflected at the output surface and cannot be wholly emitted to an outside of the LED. Even, because angles between the lateral parts of the output surface and the chip are so large, the light rays incident on the lateral parts may be totally reflected. As a result, a large light density on a central part and a small light density on the lateral parts of the output surface are formed. Thus, the LED cannot provide a uniform illumination.
Therefore, there is a need for an LED, which can provide a uniform illumination.